English
Related papers

Related papers: The evolution of classical doubles: clues from com…

200 papers

We present a study of the trends in luminosity, linear size, spectral index, and redshift of classical double radio sources from three complete samples selected at successively fainter low radio-frequency flux-limits. We have been able to…

Astrophysics · Physics 2010-04-06 Katherine M. Blundell , Steve Rawlings , Chris J. Willott

We describe the pitfalls encountered in deducing from classical double radio source observables (luminosity, spectral index, redshift and linear size) the essential nature of how these objects evolve. We discuss the key role played by…

Astrophysics · Physics 2009-10-31 Katherine Blundell , Steve Rawlings , Chris Willott , Namir Kassim , Rick Perley

The properties of a sample of 31 very powerful classical double radio galaxies with redshifts between zero and 1.8 are studied. The source velocities, beam powers, ambient gas densities, total lifetimes, and total outflow energies are…

Astrophysics · Physics 2007-08-09 Ruth Daly , C. O'Dea , P. Kharb , S. Baum , Kenneth Freeman , Matthew Mory

We do not fully understand the dynamics and evolution of a radio galaxy. Models of classical double (Type II) sources are in a reasonable state, but these objects are rare. Non-type II sources (generically called Type I) are far more…

Astrophysics · Physics 2007-05-23 Jean Eilek

Multi-frequency radio observations of the radio bridge of powerful classical double radio sources can be used to determine: the beam power of the jets emanating from the AGN; the total time the source will actively produce jets that power…

Astrophysics · Physics 2015-05-27 Lin Wan , Ruth A. Daly , Erick J. Guerra

We review the statistical properties of the main populations of radio sources, as emerging from radio and millimeter sky surveys. Recent determinations of local luminosity functions are presented and compared with earlier estimates still in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Gianfranco De Zotti , Marcella Massardi , Mattia Negrello , Jasper Wall

Recent investigations of how the median size of extragalactic radio sources change with redshift have produced inconsistent results. Eales compared the radio and optical properties of a bright 3C and faint 6C sample and concluded that…

We use the 6C** sample to investigate the co-moving space density of powerful, steep-spectrum radio sources. This sample, consisting of 68 objects, has virtually complete K-band photometry and spectroscopic redshifts for 32 per cent of the…

Astrophysics · Physics 2008-11-26 Maria J. Cruz , Matt J. Jarvis , Steve Rawlings , Katherine M. Blundell

We consider evolution properties of galaxies and quasars with steep radio spectrum at the decametre band from the UTR-2 catalogue. The ratios of source's monochromatic luminosities at the decametre and high-frequency bands display the…

Astrophysics of Galaxies · Physics 2016-10-19 Alla Miroshnichenko

At low redshifts powerful radio sources are uniquely associated with massive galaxies, and are thought to be powered by supermassive black holes. Modern 8m -- 10m telescopes may be used used to find their likely progenitors at very high…

Astrophysics · Physics 2015-06-24 Wil van Breugel

The problems of using the spectral index of radio galaxies in various tests, in particular, in selecting distant radio sources are considered. The history of the question of choosing a criterion of searching for distant radio galaxies based…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-03 O. V. Verkhodanov , M. L. Khabibullina

This review discusses three ways in which radio galaxies and other high-redshift objects can give us information on the nature and statistics of cosmological inhomogeneities, and how they have evolved between high redshift and the present:…

Astrophysics · Physics 2007-05-23 J. A. Peacock

A new sample of very large angular size radio sources has been selected from the 1.4 GHz VLA surveys: FIRST and NVSS. This sample will be very useful for an observational constraint on the time evolution of double radio sources, especially…

Astrophysics · Physics 2009-11-06 J. Machalski , M. Jamrozy , S. Zola

Many of the powerful radio galaxies observed at high redshift are very small, presumably because they are very young. A simple model, which treats the radio source as a bubble expanding into a radially stratified medium, is capable of…

Astrophysics · Physics 2007-05-23 Mitchell C. Begelman

We have formed a new sample which consists of extended extragalactic radio sources without obvious active galactic nuclei (AGN) in them. Most of these sources appear to be dead double radio sources. These sources with steep spectra ($\alpha…

Astrophysics of Galaxies · Physics 2011-02-11 K. S. Dwarakanath , Ruta Kale

We present a homogeneous and 92 % complete dataset of optical nuclear spectra for the 113 3CR radio sources with redshifts < 0.3, obtained with the Telescopio Nazionale Galileo. For these sources we could obtain uniform and uninterrupted…

Extragalactic radio sources are a unique cosmological probe in that they trace large-scale structure on scales inaccessible to other wavelengths. However as radio survey data is inherently 2D, the redshift distribution, N(z), is necessary…

Astrophysics · Physics 2007-05-23 C A Jackson , J V Wall

We investigate the dependence of the Fanaroff-Riley (FR) 1/2 dichotomy of radio galaxies on their luminosities and redshifts. Because of a very strong redshift-luminosity correlation (Malmquist bias) in a flux-limited sample, any…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-05 Ashok K. Singal , Kamlesh Rajpurohit

Bent-double radio sources can act as tracers for clusters of galaxies. We present imaging and spectroscopic observations of the environments surrounding ten of these sources (most of them Wide Angle Tails (WATs)) selected from the VLA FIRST…

Astrophysics · Physics 2009-10-31 E. L. Blanton , M. D. Gregg , D. J. Helfand , R. H. Becker , R. L. White

We constructed and presented in the first paper of this series a new sample of 84 large angular size radio galaxies by selecting from the NRAO VLA Sky Survey objects with angular size > 4', declination above +60 degrees and total flux…

Astrophysics · Physics 2009-11-07 L. Lara , I. Marquez , W. D. Cotton , L. Feretti , G. Giovannini , J. M. Marcaide , T. Venturi
‹ Prev 1 2 3 10 Next ›